Implantable surgical meshes have been widely used for a variety of different surgical procedures such as hernia repair, pelvic floor repair, urethral slings for treating fecal and urinary incontinence, implants for treating female vaginal prolapse, and many others.
For example, urinary incontinence is a disorder that generally affects women of all ages. The inability to control urination can impact a subject both physiologically and psychologically. Urinary incontinence can interfere with a person's daily activity and impair quality of life. Stress urinary incontinence is one type of urinary incontinence. Actions including straining, coughing, and heavy lifting can cause women with stress urinary incontinence to void urine involuntarily.
Various physiological conditions cause urinary incontinence in women. Stress urinary incontinence is generally caused by two conditions that occur independently or in combination. One condition, known as intrinsic sphincter deficiency (ISD), occurs when the urethral sphincter fails to coapt properly. ISD may cause urine to leak out of the urethra during stressful actions. A second condition, known as hypermobility, occurs when the pelvic floor is weakened or damaged and causes the bladder neck and proximal urethra to rotate and descend in response to increases in intra-abdominal pressure. When intra-abdominal pressure increases due to strain resulting from coughing, for example, urine leakage often results.
One method for treating stress urinary incontinence includes placing a sling to either compress the urethral sphincter or placing a sling to provide a “back stop” to the bladder neck and proximal urethra. Providing support to the bladder neck and proximal urethra maintains the urethra in the normal anatomical position, while elevation places the urethra above the normal anatomical position.
A woven or knit mesh structure for the sling (or for implants to treat other pelvic conditions) is desirable in that it allows tissue ingrowth into and through the mesh. However, problems exist in that an open weave or knit construction that will promote tissue in-growth after implantation does not necessarily lend sufficient structural support to the mesh to aid in the process of implantation. Further, providing a closed-weave mesh that has sufficient structural support for implantation does not necessarily provide sufficient porosity to promote tissue in-growth for long term stability.
Accordingly, there is a need for an improved implantable surgical mesh that reduces or alleviates the problems discussed above, that has the proper combination of mechanical rigidity and flexibility during implantation, and the proper combination of porosity and mechanical properties after implantation. According to the invention, the mesh can include degradable (absorbable) structure, and that structure can be selected to control the degradation rate of the absorbable material to provide desired mechanical properties and also promote tissue ingrowth that mirrors natural body tissue.